Really no such thing as a Directional fuse as the current flows thru the fuse and if too much current flows thru the fuse the metal will "melt" or burn thtu and then current to the device will be stopped. There is no +/- side to it. If it has a +/- on the fuse something is not right. Open your owners manual and buy the Mfg fuse for the unit vs some aftermarket fuse and call the tech dept and ask the experts for the unit.